Re: [GIT pull] x86/pti: The real thing

[Mike Galbraith]

On Fri, 2017-12-29 at 17:42 -0800, Linus Torvalds wrote:
> On Thu, Dec 28, 2017 at 12:34 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >
> > please pull the latest x86-pti-for-linus git tree from:
> >
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-pti-for-linus
> >
> > This is the final set of enabling page table isolation on x86:
> 
> Ok, after that late MCORE2 scare that held things up, this is now
> merged in my tree and pushed out. "WorksForMe(tm)".

But it definitely ain't free.  NFS hanging out in the kernel for 82ms
at a whack may not be such a bad idea after all ;-)

i4790+tbench

CONFIG_PAGE_TABLE_ISOLATION=y
Throughput 3467.72 MB/sec  8 clients  8 procs  max_latency=3.499 ms

CONFIG_PAGE_TABLE_ISOLATION=n
Throughput 3700.81 MB/sec  8 clients  8 procs  max_latency=4.893 ms

CONFIG_PAGE_TABLE_ISOLATION=y                CONFIG_PAGE_TABLE_ISOLATION=n
4.48%  [k] syscall_return_via_sysret         3.56%  [k] copy_user_enhanced_fast_string
3.41%  [k] copy_user_enhanced_fast_string    2.54%  [.] child_run
2.48%  [.] child_run                         1.76%  [k] tcp_transmit_skb
1.64%  [.] __strchr_sse2                     1.74%  [k] tcp_recvmsg
1.60%  [k] tcp_transmit_skb                  1.69%  [.] __strchr_sse2
1.55%  [k] tcp_recvmsg                       1.56%  [.] __GI_____strtoll_l_internal
1.46%  [k] ipt_do_table                      1.44%  [k] ipt_do_table
1.45%  [.] __GI_____strtoll_l_internal       1.42%  [k] tcp_sendmsg_locked
1.25%  [k] tcp_in_window                     1.34%  [k] tcp_write_xmit
1.21%  [.] next_token                        1.34%  [k] tcp_clean_rtx_queue
1.17%  [k] tcp_clean_rtx_queue               1.26%  [.] next_token
1.16%  [k] tcp_sendmsg_locked                1.24%  [k] tcp_in_window
1.15%  [k] __switch_to                       1.19%  [k] nf_conntrack_in
1.10%  [k] switch_mm_irqs_off                1.17%  [k] __switch_to
1.09%  [k] tcp_write_xmit                    1.13%  [.] __strcasecmp_l_avx
1.09%  [k] tcp_ack                           1.10%  [k] switch_mm_irqs_off
1.08%  [k] nf_hook_slow                      1.08%  [k] tcp_v4_rcv
1.04%  [k] __sched_text_start                1.06%  [k] nf_hook_slow
0.99%  [.] __strcasecmp_l_avx                1.05%  [k] tcp_ack